Rock anchor grouting tool

ABSTRACT

A grouting tool includes a body element having a body element leading end and a body element trailing end. A collet member having a collet member trailing end in fluid communication with the body element leading end, and a collet member leading end having a hollow passage adapted to receive a grout tube. A grout injection port is secured to the body element trailing end. A portion of the collet member is radially compressible to provide a clamping force adapted to secure the grout tube to the grouting tool.

FIELD OF THE INVENTION

The present invention relates to a rock anchor grouting tool. In particular, the present invention relates to a tool for assisting during the grouting of certain anchors used in mining and civil applications.

BACKGROUND OF THE INVENTION

Various types of rock anchors are used in mining and civil applications to stabilise a region of a strata to reduce the risk of collapse. In recent years in the coal mining industry, there has been a trend towards the use of cable anchors in place of conventional rigid bolts. A cable anchor may be in the form of a multi-wire tendon, a single strand of cables or a number of strands. In some instances the strands may be encased in a steel tube.

One style of rock bolt which is being increasingly deployed utilises a bulbed cable. This is a cable that has a number of bulbs or cages formed along the length of the cable which are each defined by a portion of the cable which is locally radially enlarged, thereby locally increasing the diameter of the cable outwardly at predetermined positions along the length of the cable. The bulbs assist with the bonding with the cementatious grout, and generally holding the bolt in abutment against the rock strata. One commonly used bulbed cable bolt is about 15.2 mm in outer diameter, and utilises a “fish hook” arrangement to temporarily secure the bolt in position prior to grout insertion. Resin securement is not normally required with this style of cable bolt.

The fish hook arrangement utilises two or more barbs which are swaged or otherwise connected to the tip of the cable bolt at the leading end. The barbs extend angularly outwardly and rearwardly away from the leading end of the cable bolt. As such, the tips of the barbs abut against and engage the side wall of the drilled hole, providing sufficient force to prevent the anchor from being removed from the hole before the resin and/or grout have been applied.

In order to install the bolts, holes are initially drilled which are approximately 200 mm shorter than the cable bolt length. The holes are installed by hand held drilling machines or by mobile bolters. The cable bolts are available in various lengths depending on factors such as the geological strata, and the type of rock to be supported. The cable bolt is longer than the drilled hole such that a portion of the bolt extends out of the hole after insertion. This tailing end of the bolt is used for tensioning the bolt relative to the geological strata.

Before insertion into the drilled hole, the bulbed cable bolt is prepared by attaching an air breather tube along the length of the bolt. A breather tube extends along the length of the bolt and has an opening located near the leading end of the bolt. The breather tube serves the purpose of permitting air to escape from the hole as the hole is filled with grout.

In addition to the breather tube, a grout injection tube is also attached to the cable bolt. The grout injection tube has a tip which extends into the drilled hole, and a tail which extends out of the hole, with sufficient tail length to connect to a grouting pump.

During installation, the bulbed cable bolt is inserted into the hole and the mouth of the hole around the bolt is substantially sealed to reduce the risk of loss of any grout during pumping.

The grout tube is then connected to a grout pump. The trailing end of the air breather tube may then be placed into a receptacle of water. Pumping of the grout then commences. Air bubbles which exit from the air breather tube during pumping are visible in the water. When the drilled hole is fully grouted the air bubbles cease to flow, indicating to the grout operator that the process is completed, and the grouting tool can be disconnected. Once the grout has cured, the cable bolt can be tensioned if required.

A disadvantage with some existing grouting techniques is that it can be difficult for the user to connect the leading end of the lance with the fitting located at the trailing end of the cable bolt. This is because depending on the clearance of the tunnel or mine between the floor and the ceiling, the user is often standing a considerable distance below the bolt. Accordingly, the user must align the lance and the bolt without the aid of any visual or tactile assistance. In addition, when the floor and the ceiling are non-parallel, the two fittings may be angularly misaligned, which can be difficult to observe from the user's location beneath the anchor.

It can take several minutes for a user to successfully engage the grout lance and the anchor, which significantly delays the grouting process, and such delays are magnified when there are numerous anchors requiring grouting.

Further problems with grouting tools concern the amount of time required to connect the tool to the cable bolt. When a large matrix of cable bolts need to be grouted, a small loss of time on each cable anchor can add significantly to the overall time required to complete the task.

A still further problem with some grouting tools is the difficulty in cleaning the tool at the end of grouting. Areas that are difficult to clean can become blocked once the grout cures, damaging the tool or reducing the efficiency of the tool or grout flow through the tool.

It is an object of the present invention to substantially overcome or at least ameliorate one or more of the above disadvantages, or at least to provide a useful alternative.

SUMMARY OF THE INVENTION

The present invention provides a grouting tool comprising: a body element having a body element leading end and a body element trailing end; a collet member having a collet member trailing end in fluid communication with the body element leading end, and a collet member leading end having a hollow passage adapted to receive a grout tube; a grout injection port secured to the body element trailing end; wherein a portion of the collet member is radially compressable to provide a clamping force adapted to secure the grout tube to the grouting tool.

The collet member preferably includes a first longitudinally extending slot.

The collet member preferably includes a circumferentially extending slot which extends generally perpendicular to and intersects with the first longitudinally extending slot.

The grouting tool further preferably includes a second longitudinally extending slot, wherein a resilient arm is defined by the first and second longitudinally extending slots and the circumferentially extending slot.

The grouting tool preferably comprises a first lever pivotally connected to the collet member.

The grouting tool further preferably comprising a clevis shaped element which includes two clevis arms and a central attachment region which is connected to the collet member, wherein the first lever is pivotally connected to the two clevis arms.

The first lever preferably includes a first engagement formation adapted to engage with the collet member.

The first engagement formation is preferably defined by a projection adapted to abut against the collet member.

The grouting tool further preferably comprises a second lever pivotally connected to the body element.

The first lever preferably includes a first lever engagement formation and the second lever includes a corresponding second lever engagement formation.

Preferably the first lever engagement formation includes a pin and the second lever engagement formation includes a slot.

The second lever preferably includes a handle.

The grouting tool further preferably comprises a locking pin, the locking pin extending through a hole formed in the body element and a corresponding threaded hole formed in the grout injection port, the locking pin having a threaded shaft for securing the grout injection port to the body element.

The body element preferably includes a body element slot.

The grout injection port preferably includes a nozzle, the nozzle being located within the body element adjacent to the body element slot.

The nozzle preferably includes an annular rubber grommet.

The grout injection port preferably includes a cut-out which engages with a corresponding projection formed on the body element.

BRIEF DESCRIPTION OF THE DRAWINGS

A preferred embodiment of the invention will now be described by way of specific example with reference to the accompanying drawings, in which:

FIG. 1 is a partially exploded view depicting a rock anchor grouting tool according to the invention;

FIG. 2 depicts the rock anchor grouting tool of FIG. 1 in an assembled configuration;

FIG. 3 depicts the rock anchor grouting tool of FIG. 1 secured to a grout tube;

FIG. 4 is a detail of a grout injection port of the rock anchor grouting tool of FIG. 1;

FIG. 5 is a perspective view of a rock anchor grouting tool according to a second embodiment of the invention;

FIG. 6 is a side view of the rock anchor grouting tool of FIG. 5 in an open position; and

FIG. 7 is a side view of the rock anchor grouting tool of FIG. 5 in a closed position.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A rock anchor grouting lance or tool 100 is depicted in the drawings. The grouting tool 100 is in particular intended for use with bulbed cable bolts, but it will be appreciated by those skilled in the art that it may be used with other cable bolt anchors.

The tool 100 includes a body element 200. The body element 200 is defined by a hollow tubular body, having a leading end 202 and a trailing end 204.

In the first embodiment of the invention, depicted in FIGS. 1 to 4, at least one body element slot or bleeder hole 210 is formed in the wall of the body element 200. In the embodiment depicted in FIGS. 1 to 4, there are two slots 210 which are diametrically opposed around the perimeter of the body element 200. The leading end 202 of the body element 200 is connected to a longitudinally extending collet member 220. However, in the second embodiment depicted in FIGS. 5 to 7, the grout bleed function is provided by the circumferentially extending slot 232 (discussed below).

The collet member 220 has a hollow tubular body defining a trailing end 222, and a leading end 224. A hollow passage extends through the tubular body and is adapted to receive a flexible grout fill tube 900 (best seen in FIG. 3). The collet member 220 includes at least one longitudinally extending slot 230. As shown in the drawings, the longitudinally extending slot 230 may be connected to a generally perpendicular circumferentially extending slot 232 located adjacent to the trailing end 222.

In one embodiment there are first and second longitudinally extending slots 230 and a circumferentially extending slot 232 extends between the first and second longitudinally extending slots 230, thereby defining a resilient arm 240 which forms part of the collet member 220, but is only attached to the collet member 220 at a single bridge or connection 244. As such, the resilient arm 240 is resiliently flexible relative to the connection 244, permitting a tip 250 of the arm 240 to move radially relative to the collet member 220.

A clevis shaped element 300 is secured to the collet member 220. The clevis shaped element 300 may be integrally formed, secured with fasteners or otherwise attached to the collet member 220. The clevis shaped element 300 includes two clevis arms 302, 304 and a central attachment portion 310 which is connected to the collet member 220. In the embodiment depicted in FIGS. 5 to 7, the clevis shaped element is attached to the collet member with a fastener extending through a hole 305 formed in the clevis shaped element 300.

A first lever 400 is pivotally connected to the arms 302, 304 of the clevis shaped element 300, with at least one suitable fastener 410. The first lever 400 includes a first engagement formation 420 in the form of a projection which is adapted to abut against the collet member 220, adjacent to the trailing end of the collet member 220, and in particular the resilient arm 240. In the embodiment depicted in the drawings, the first engagement formation 420 is defined by a bolt and nut. However, it will be appreciated by those skilled in the art that the first engagement formation 420 may be formed by an integrally formed protection or lug extending away from the first lever 400 or another such projection. In some embodiments, the depth and/or position of the first engagement formation 420 may be adjusted.

The first lever 400 includes a first lever engagement formation in the form of a pin 440 which projects generally perpendicular to a longitudinal axis of the first lever 400. In the embodiment depicted in FIGS. 5 to 7, the pin 440 is defined by a bolt which passes through a hole formed in the first lever 400.

The rock anchor grouting tool 100 includes a second lever 500. The second lever 500 is pivotally connected to the body element 200 with a suitable fastener 502 such as the screw or bolt 502 depicted in the drawings. The second lever 500 includes a second lever engagement formation in the form of a cut-out or slot 510. The cut-out 510 is adapted to receive the pin 440. The second lever 500 also includes a handle 520. In the embodiment depicted in the drawings, the handle 520 is located at a distal end of the second lever 500, furthest from the body element 200.

The grouting tool 100 includes a grout injection port 600. The grout injection port 600 is located at a trailing end of the tool 100. The grout injection port 600 has a trailing end 610 which is connectable to a grout pump (not shown). A leading end 620 of the of the grout injection port 600 is insertable into the trailing end 204 of the body element 200. The leading end 620 of the of the grout injection port 600 includes a nozzle 630 with a chamfered or filleted tip 631. The nozzle 630 has an outer diameter which is smaller than the internal diameter of the grout feed tube 900 which is associated with the cable bolt. A shoulder 640 is defined between the nozzle 630 and the grout injection port 600. The nozzle 630 includes a seal such as an annular rubber grommet or O-ring 632 which assists in sealing the nozzle 630 to the tube 900.

The grout injection port 600 includes a blind hole 650, which is typically around 1 mm deep. The hole 650 aligns with a corresponding threaded hole 260 (see FIGS. 2 and 3) which is formed on the outside of the body element 200.

A locking pin or wing bolt 700 has a threaded shaft which is insertable through the hole 260 and engages with the blind hole 650. This acts to secure the grout injection port 600 to the body element 200. The grout injection port 600 includes a cut-out 680 which engages with a corresponding projection 216 formed on the body element 200. The engagement between the cut-out 680 and the projection 216 prevents rotation of the grout injection port 600 relative to the body element 200. The locking pin 700 includes a hole 701 which can be used to secure the locking pin 700 to a hook, a users belt or another such item to prevent it from being misplaced, for example during cleaning of the tool 100.

The operation of the grouting tool 100 will now be described. When a user wishes to grout a cable bolt, the bulged cable bolt is inserted into a predrilled hole, and is initially held in position by the fish hook formation at the leading end of the cable bolt. The grout fill tube 900 which is manufactured from a flexible polymer tube extends some distance beyond the opening of the hole drilled in the geological strata, and is generally long enough to reach near to the ground where grouting technicians can readily operate.

The poly pipe grout fill tube 900 enters into the leading end 224 of the collet member 220. The user can visually inspect through the body element slot 210 to confirm when the grout fill tube 900 has proceeded to the desired location, in which the nozzle 630 has entered the trailing end of the grout fill tube 900. The end of the grout fill tube 900 comes to rest against the shoulder 640.

The user then places the pin 440 of the first lever 400 into the cut-out 510 of the second lever 500. By applying a force to the handle 520, pulling the handle 520 toward the grout injection port 600, the first lever 400 is pivoted about the fastener 410, and the engagement formation 420 applies a force against the collet member 220. This results in the collet member 220 being radially compressed, thereby applying a clamping force to the poly pipe grout fill tube 900. The clamping force prevents the poly pipe 900 from being withdrawn from the collet member 220. After clamping, grout pumping commences as required.

FIG. 6 depicts the grouting tool 100 in the open position, before the clamping force is applied. In contrast, FIG. 7 depicts the grouting tool 100 in the closed position, in which the clamping force is applied to the poly pipe grout fill tube 900.

On completion of grouting, the clamping process is reversed by pivoting the second lever 500 toward the collet member 220.

Advantageously, the locking pin 700 can be selectively removed. This permits the body 200 and grout injection port 600 to be separated for washing and cleaning

Although the invention has been described with reference to specific examples, it will be appreciated by those skilled in the art that the invention may be embodied in many other forms. 

I claim:
 1. A grouting tool comprising: a body element having a body element leading end and a body element trailing end; a collet member having a collet member trailing end in fluid communication with the body element leading end, and a collet member leading end having a hollow passage adapted to receive a grout tube; a grout injection port secured to the body element trailing end; wherein a portion of the collet member is radially compressible to provide a clamping force adapted to secure the grout tube to the grouting tool.
 2. The grouting tool of claim 1, wherein the collet member includes a first longitudinally extending slot.
 3. The grouting tool of claim 2, wherein the collet member includes a circumferentially extending slot which extends generally perpendicular to and intersects with the first longitudinally extending slot.
 4. The grouting tool of claim 3, further including a second longitudinally extending slot, wherein a resilient arm is defined by the first and second longitudinally extending slots and the circumferentially extending slot.
 5. The grouting tool of claim 1 comprising a first lever pivotally connected to the collet member.
 6. The grouting tool of claim 5, further comprising a clevis shaped element which includes two clevis arms and a central attachment region which is connected to the collet member, wherein the first lever is pivotally connected to the two clevis arms.
 7. The grouting tool of claims 6, wherein the first lever includes a first engagement formation adapted to engage with the collet member.
 8. The grouting tool of claim 7, wherein the first engagement formation is defined by a projection adapted to abut against the collet member.
 9. The grouting tool of claim 5, further comprising a second lever pivotally connected to the body element.
 10. The grouting tool of claim 9, wherein the first lever includes a first lever engagement formation and the second lever includes a corresponding second lever engagement formation.
 11. The grouting tool of claim 10, wherein the first lever engagement formation includes a pin and the second lever engagement formation includes a slot.
 12. The grouting tool of claim 9, wherein the second lever includes a handle.
 13. The grouting tool of claim 1, further comprising a locking pin, the locking pin extending through a hole formed in the body element and a corresponding threaded hole formed in the grout injection port, the locking pin having a threaded shaft for securing the grout injection port to the body element.
 14. The grouting tool of claim 1, wherein the body element includes a body element slot.
 15. The grouting tool of claim 14, wherein the grout injection port includes a nozzle, the nozzle being located within the body element adjacent to the body element slot.
 16. The grouting tool of claim 15, wherein the nozzle includes an annular rubber grommet.
 17. The grouting tool of claim 1, wherein the grout injection port includes a cut-out which engages with a corresponding projection formed on the body element. 